As the opposite of centralized design, the notion of distributed design, where each subcontroller is designed independently of the others, has been introduced [1]}.
Despite its practical importance, few studies on distributed design are available in the literature owing to the technical difficulty that each subcontroller must be designed to be capable of handling variations of the other subcontrollers.
To overcome this obstacle, several sophisticated distributed design methods have been proposed over the last decade.
As a distributed design method of decentralized controllers, retrofit control has been proposed [2]}, [3]}, [4]}.
Distributed design methods of distributed controllers having a general communication topology have also been proposed[1]}, [6]}, [7]}, [8]}, [9]}, [10]}, [11]}, [12]}, [13]}.
